【作者】 马金妍；

【导师】 王开运；

【作者基本信息】 华东师范大学 ， 生态学， 2010， 硕士

【摘要】 水是维系湿地生态系统稳定和健康的决定性因子,其中水位梯度是湿地生态系统中重要的环境梯度之一,水位波动是控制湿地特征的关键因子,是湿地典型的扰动特征之一。湿地土壤也是湿地生态系统的重要组成部分,它既是湿地获取化学物质的最初场所,又是湿地发生化学变化的中介,还是湿地植物的直接支撑者。湿地的水分条件、水位变化及湿地土壤的类型、结构和肥力状况会影响到湿地生态系统植物群落的分布及其生产量、群落的稳定性、物种多样性和群落的演替。因此,研究湿地优势建群种对湿地水位波动和土壤环境因子变化的响应具有重大的现实意义。崇明岛是上海市最主要的土地战略储备区,滩涂围垦形成了崇明现在岛域面积的43.7%。在各次围垦过程中,人为的排水脱盐行为使围垦区湿地的无机环境发生了改变,植物群落构成也发生了相应的变化。本研究的地点位于崇明东滩围垦区的湿地修复示范区,区内对主要河道的水位进行人工控制。采用样方法记录区内不同河道边芦苇的生长过程,从水位波动和土壤环境角度来解释芦苇生长和繁殖的差异,进而量化水位和土壤环境因子与芦苇生长和繁殖之间的关系,为进一步可持续利用中芦苇群落的保育与修复提供基础数据,同时为滨海围垦湿地的恢复和重建提供科学依据。主要研究结果和结论如下：1.研究区域样地间的水位存在差异,且该区域水位有如下特点：春季以地表淹水为主,夏秋季节以地下水位为主,三样地水位在秋季处于最低值(样地1平均水位-46.81±23.40cm,样地2为-23.62±15.81cm,样地3为-15.50±8.94cm)。2.随着季节的更替,各样地土壤的容重和有机质呈“V”字变化(夏季最低),全氮含量逐渐下降。样地内的土壤容重总体上高于正常范围,即：1.1～1.4g/cm3,有机质和全氮含量偏低。各样地不同季节的土壤容重和有机质不存在差异,三样地秋季时的土壤全氮间存在差异。各季节三样地土壤含水量随着垂直深度的增加而增大,且各层(0-20cm、20-40cm、40-60cm)土壤含水量都与水位密切相关。三个季节中,春季的表层(0-20cm)土壤含水量是最大的：样地1为306.1±16.4 g/kg,样地2为362.4±9.7 g/kg,样地3为408.4±20.7g/kg；夏季,三样地的表层(0-20cm)土壤含水量存在差异；秋季,三样地20cm以下的土壤含水量存在差异。3.三样地芦苇种群在密度、株高、基径、单株叶数和叶面积、地上生物量方面的生长动态记录如下：密度最大值出现在夏季的2号样地(152±13棵/m2)；基径最大值出现在春季的1号样地(7.35±0.31mm),单株叶面积最大值是夏季的3号样地(547.69±16.67cm2),株高、单株叶数和地上生物量的最大值出现在秋季的3号样地。该区域芦苇地上生物量主要由株高和基径决定,而且株高对地上生物量的贡献比基径大。秋季,芦苇繁殖状况各指标(开花率、花数、种子数量)的最高值均出现在3号样地,且各指标样地间均存在差异。4.通过分析水位、土壤环境因子与芦苇生长和繁殖的关系,可得出：当水位高于地表时,芦苇的生长状况直接与水位有关；当水位低于地表时,芦苇的生长状况和繁殖状况与不同层次土壤含水量有关,同时土壤容重和全氮含量也决定了芦苇株高、花数与种子数量。总之,低土壤含水量、低全氮含量和高容重的环境不利于芦苇的生长和繁殖。更多还原

【Abstract】 Water is the decisive factor to keep the wetland ecosystem stable and healthy, and water level gradient is an important environmental gradient in wetland ecosystem. The fluctuation of water level is not only the key factor which controlled the wetland characteristics but also one of the typical disturbance characteristics of the wetland. Wetland soil is an important part of wetland ecosystem, it is the first place for wetland to obtain chemical substances, and wetland soil is also the intermediary of chemical changes and the direct supporter of wetland plants. The water condition and the fluctuation of water level and soil type, structure and fertility in wetland will affect wetland plant’s community distribution and production, community stability, species diversity and community succession. Therefore, it has a great practical significance to research the wetland constructive species in response to fluctuation of water level and soil environmental factors.Shanghai Chongming Island is the most important strategic reserve of land area, the 43.7% of whose area is formed by beach reclamation. During the process of beach reclamation, artificial reclaimed water desalination changes the inorganic wetland environment, and the corresponding plant community composition also changes. The study site is located in the wetland restoration demonstration area of reclaimed land area and the water level of major rivers is controlled. Growth of Phragmites australis in different channels is recorded by sampling method and the reason of differences in Phragmites australis growth and reproduction is explained from water level fluctuations and soil aspects. Based on the research above, we can quantify the relationships between water level, soil environmental factors and growth, reproduction of Phragmites australis, and further to provide basic data for the sustainable use of conservation and restoration of Phragmites australis community, and also to provide a scientific basis for restoration and reconstruction of reclaimed wetland. The main findings and conclusions are as follows:1. The plots in study area has differences in water level, and the water level of the region in spring is mainly surface flooding, summer and autumn is mainly underground water level, the water level in three plots is the lowest in autumn:the average water level of plot 1 is -46.81±23.40 cm, plot 2 is -23.62±15.81cm, plot 3 is-15.50±8.94cm.2. Soil bulk density and organic matter of the plots change with the season as "V" trend, and lowest in summer, soil total nitrogen content decreased with seasonal variation; soil bulk density of plots is above the normal range of 1.1～1.4g/cm3; soil organic matter and total nitrogen are on the low side. Soil bulk density and organic matter are not different between the various seasons in each plot, but soil total nitrogen has differences among the plots only in the fall. In each season, soil water content of three plots increase along with the vertical depths, and the soil water contents of each layer (0-20cm、20-40cm、40-60cm) are closely related with water level. In spring, soil water content of surface layer (0-20cm) is the maximum of three seasons:plot 1 is 306.1±16.4g/kg, plot 2 is 362.4±9.7g/kg, plot 3 is 408.4±20.7g/kg; in summer, soil water content of surface layer (0-20cm) are different between the three plots; in autumn, soil water content of the layer below 20cm varies between the three plots.3. The growth dynamics of the Phragmites australis population density, plant height, basal diameter, leaf number and leaf area per plant, aboveground biomass in the three plots are recorded:the density maximum appears in the summer in plot 2, 152±13N/m2; base diameter maximum is in the spring of plot 1:7.35±0.31mm, the maximum leaf area per plant is in summer in plot 3:547.69±16.67cm2, the maximums of stem length, leaf number per plant and aboveground biomass are in plot 3 in the fall. While the aboveground biomass of Phragmites australis in this region major decision by plant height and basal diameter, and plant height on the contribution of biomass larger than base diameter. The reproduction conditions indexes of Phragmites australis (flowering rate、the number of flowers and seeds) in plot 3 are at the highest values, and each index is different between plots in autumn. 4. From the analysis of the relationship between water level、soil environmental factors and growth and reproduction of Phragmites australis, we can get:when the water level is above the surface, the reed’s growth status is directly related to the water level; when the water level is below the surface, the Phragmites australis growth status and reproduction condition are related with the different levels of soil water content, meanwhile soil bulk density and total nitrogen content also determine the reed plant height, the number of flowers and seeds. Above all, the environment of low soil water content, low soil total nitrogen content and high soil bulk density is not conducive to the growth and reproduction of Phragmites australis.更多还原